<template>
     <div>
         <p>我是comB:{{price}}</p>
         <input type='text' v-model="input_val">
    </div>
</template>
<script>
export default {
  name: 'comA',
  props:['AppToComA'],
  data() {
    return {
        input_val:0
    }
  },
  computed: {
      price:function(){
          return this.input_val+1
      }
  }
};
</script>